2008 Annual Monitoring Report (pdf 10.9MB) - Bolsa Chica ...

Bolsa Chica Lowlands Restoration Monitoring
2008 Annual Report
All fish captured in the nets were transferred to buckets or tubs filled with seawater, worked up, and
released. Data collected for fish caught in each haul included species identification, individual counts,
standard length (in millimeters [mm]), and wet weight (in grams [g]). Ectoparasites, lesions, or
tumors, if any, were also noted. Species that were not identified in the field were transported to the
laboratory and identified utilizing field identification references and/or a dissecting microscope. All
fish identifications were made using widely accepted field identification guides such as Miller and Lea
(1972) and Eschmeyer et al. (1983). Fish nomenclature was standardized in conformance with Nelson
et al. (2004).
If more than 30 individuals of a species were caught in a replicate of any gear type, a batch sampling
procedure was utilized. First, the standard length and weight was measured for 30 randomly selected
individuals within the species. Second, the batch weight was measured for 100 additional randomly
selected individuals. Finally, the total weight was measured for all of the remaining, uncounted
individuals caught in the replicate. The number of uncounted individuals was then estimated using the
batch weight of the 100 randomly selected individuals.
All survey data were initially recorded in the field on hard copy data sheets and later transferred to a
digital database and checked for accuracy.
Due to the difficulty of rapidly and conclusively distinguishing between small arrow goby
(Clevelandia ios) and shadow goby (Quietula y-cauda) in the field, gobies that may have belonged to
either species were identified as "arrow/shadow goby complex". These functionally similar species
commonly co-occur and occupy similar niches in the demersal fish community. Vouchers of the
gobies collected were brought back to the lab for identification to document the actual species present
at a given station.
All macroinvertebrates captured in the fish sampling nets were collected, identified to the lowest
taxonomic level possible, counted, and released. Due to the tremendous spatial variability of these
species and the non-targeted methodology employed here to sample them, collected data were intended
to generate a list of species that occur in the project area, rather than to provide definitive density and
biomass data on their populations. The data are presented in the following section covering benthic
invertebrates.
At each study location, physical water quality parameters were measured coincident with the biological
sampling described above. A Hydrolab Quanta ® multi-probe, calibrated in accordance with
manufacturer specifications, was used to collect temperature, dissolved oxygen, turbidity, and salinity
data. Readings were taken near the bottom and top of the water column.
Results
A total of 42 fish species were captured in 2008 quarterly fish sampling. The sampling results are
presented below by sampling area: Full Tidal Basin, Muted Tidal Basins, and Muted Pocket Marsh.
Full Tidal Basin
A total of 39 species of fish were captured in the FTB in 2008 (Table 1-5). The greatest number of fish
was captured at Station 2 (the southern station closer to the inlet), made up of 33 species and
dominated by topsmelt (Atherinops affinis) (60% of the total catch). California grunion (Leuresthes
tenuis) accounted for 12%, unidentified atherinid juveniles (Atherinidae) 9%, arrow/shadow gobies
Merkel & Associates, Inc. 40